DESCRIPTION (provided by investigator): Among young men, sexually transmitted infection (STI) prevalence rates increase rapidly from middle to late adolescence, and reduction of adolescent STI is an important public health goal of Healthy People 2010. Prevention efforts, however, are hampered by a limited understanding of incident STI across this key developmental period. The purpose of this study is to examine, longitudinally, incident infections with three common bacterial STI (Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis) among young men from middle to late adolescence. The specific aims are: (1) to describe young men's acquisition and sequence of these three STI through adolescence as a function of time;(2) To examine the associations among young men's concurrency, partner-specific STI risk behaviors and incident STI infection through adolescence;and (3) to examine how developmental changes in relationships and social contexts are associated with STI risk behaviors and incident infection with the above three STI through adolescence. The applications will recruit 200 African American, Latino and Euro-American young men, ages 14-17 at enrollment, from a community with high STI prevalence. Participants will be followed for up to 24 months and complete the following: (1) monthly surveillance urine samples for C. trachomatis, N. gonorrhoeae and T. vaginalis to describe the acquisition, sequence and pattern of incident STI across adolescence;(2) quarterly audio computer assisted self interviews to characterize demographic, behavioral, and socio-cultural correlates of incident STI;and (3) daily cell phone diaries to describe symptom development of incident STI, and to characterize the immediate behavioral phenomena associated with incident STI, including condom use and partner concurrency. The proposed research addressed three priorities related to STI: (1) A focus on adolescents, (2) The interactions among different organisms, and (3) the provision of key developmental epidemiology and behavioral data to inform interventions. PUBLIC HEALTH RELEVANCE: Project Narrative Sexually transmitted infections (STI) are a significant public health problem for adolescent men, with marked disparities by race and ethnicity. Prevention is hampered by limited knowledge about how STI develops across adolescence. The purpose of this research is to longitudinally describe patterns of, and risk factors for, incident infections with three common bacterial STIs among multi-ethnic 14 to 17 year old young men.